Russian opposition leader Alexei Navalny and around 1600 anti-Kremlin activists have been detained by police during street protests against Vladimir Putin ahead of his inauguration for a fourth term as president.
Navalny had called for demonstrations in more than 90 towns and cities across Russia against what he says is Putin's autocratic, tsar-like rule.
Before his detention, he briefly addressed supporters in central Moscow, leading them in chants of 'Down with the Tsar!".
"They said that this city belongs to Putin. Is that right?" Navalny asked his supporters. "Do you need a tsar?" he asked, eliciting a collective roar of "No!"
Putin won re-election overwhelmingly in March, extending his grip over Russia for six more years - a tenure of 24 years that would make him Moscow's longest-serving leader since Soviet dictator Josef Stalin.
Navalny, who was barred from running in the election on what he says was a false pretext, was detained soon after showing up on Moscow's Pushkin Square, where young people were chanting "Russia without Putin!" and "Putin is a Thief!".
Video footage showed five policemen hauling him to a waiting van by his arms and legs, a scene that was repeated dozens of times with his supporters.
Another opposition politician, Ilya Yashin, said police planned to charge Navalny with disobeying a police officer. The penalty for such an offence, if repeated, can be a fine and up to 30 days in jail.
Early on Sunday, shortly after the midnight, Navalny said on Twitter that he had been released by the police pending court.
Navalny, who has been detained and jailed numerous times for organising similar protests, said he was proud to have made it to the rally.